1. Field of the Invention
The present invention relates to communication systems such as wireless local area networks (WLANs).
2. Description of the Related Art
IEEE 802.15.3 and IEEE 802.11, both of which are incorporated herein by reference in their entireties, are two standards directed to communications within WLANs. The IEEE 802.15.3 standard is designed to support isochronous streams for time-sensitive multimedia data, while the IEEE 802.11 standard is more suitable for asynchronous data that is less sensitive to delays in transmission. Although the IEEE 802.15.3 specification defines a completely different wireless physical (PHY) layer from that of the IEEE 802.11 specification, both standards define solutions for the 2.4 GHz Industrial, Scientific, Medical (ISM) band. There is, therefore, a high probability that devices employing the two standards will be used within range of one another and thereby cause mutual destructive interference.
LinCom Wireless of Los Angeles, Calif., proposed a coexistence method for IEEE 802.15.3 devices named “Harmony,” in which an IEEE 802.15.3 device might detect and interpret the type and duration of a competing system's co-channel transmissions and remain off-the-air for that duration. Coexistence with IEEE 802.11a, IEEE 802.11b, and/or ETSI HipeRLAN-2 systems might be achieved in this way. This technique would require an IEEE 802.15.3 system to defer channel access to other standards-based systems, which would severely effect the ability of the IEEE 802.15.3 system to reliably deliver time-sensitive streams of multimedia data.
Mobilian Corporation of Hillsboro, Oreg., proposed and implemented a collaborative coexistence method for IEEE 802.11b devices and devices conforming to the Bluetooth specification. Part of this solution involves time-slicing the use of the Bluetooth and IEEE 802.11 media access rules within a combined radio device to ensure minimal destructive interference between the radios. This technique simply manages and mitigates destructive interference caused by a single device (e.g., a laptop computer) that simultaneously uses both an IEEE 802.11b radio and a Bluetooth radio. The solution does not involve informing nearby IEEE 802.11 devices of the need to remain quiescent for the duration of the Bluetooth radio's transmissions.